experiment 2: some features

Title: SOME FEATURES OF THE CHEMISTRY OF GROUP IIA

ABSTRACT
Group II of the periodic table consists of alkaline earth metals, including beryllium,
magnesium, calcium, strontium, barium, and radium. These elements are highly
reactive due to their readily give-up valence electrons. Their metallic properties
cause them to donate electrons in chemical reactions. The purpose of this
experiment was to look at Group IIA reactions with beryllium, magnesium, and
calcium salts. The pH of 0.1M solutions of beryllium sulphate, magnesium chloride,
and aluminum chloride was tested using pH paper. Aqueous ammonia and weak
hydrochloric acid were added to the solutions. The solution was diluted with water
and heated. Ammonium carbonate was added to the solutions. The solution was
treated with ammonia and glacial acetic acid. The solubility of the dry product was
investigated in water, ethanol, diethyl ether, and light petroleum. Calcium is the most
reactive element, producing precipitates in solutions. Magnesium is the second most
reactive metal, with Be having a weak interaction with anion solutions like carbonate
ions.

INTRODUCTION
The elements of Group II of the periodic table are the alkaline earth metals. They
were given this name because they were initially isolated from a combination in
which they were associated with oxygen (Rayner & Zheng, 2008). These were
referred to as the earth by early chemists. The name "alkaline" comes from the fact
that they formed an alkaline or basic pH solution in water. The group consists of
beryllium, magnesium, calcium, strontium, barium, and radium (Smith, 2015) .
Because all alkaline earth metals have two valence electrons that they readily give
up, they are all exceedingly reactive. Beryllium and aluminum have a diagonal
connection, which means they experience similar reactions and have similar
chemical properties.

The metallic property gives the tendency to donate electrons in chemical reactions of
Group II elements as the number of metal groups increases. The group 2 element
that reacts the quickest with water produces alkaline (hydroxides) and hydrogen gas.
Such a response could manifest itself as follows: Ca(s) + 2H2O Ca(OH)2 (aq) + H2.
When calcium and water mix, they form a base and hydrogen gas. As the metallic
nature of a metal declines, so does its ability to produce ions. Metals give up
electrons to form ions. As you progress down the group, the electrons become
farther from the nucleus and more attracted to other elements, causing the atoms to
grow, and making it easier for other elements to steal their electrons.

The pH value of a solution reflects how acidic or basic it is. The solubility of alkali
metals, earth metals, sulphate, and carbonates decrease as you move down the
group. Carbonates of all group II metals are insoluble. To keep their inert state, these
dazzling white metals must be kept away from air and water. The reactivity of
magnesium and calcium, two of the most common alkaline metals, will be examined
in this experiment. Water will be added to the metals and the reaction will be
monitored to see how they respond. An alkaline solution will be formed if the metals
do not react with the water.

AIM AND OBJECTIVES

To investigate Group IIA reactions utilizing beryllium, magnesium, and calcium salts.
To compare these reactions to aluminum's.

MATERIALS AND METHOD

The pH of 0.1M solutions of beryllium sulphate, magnesium chloride, and aluminum
chloride was tested using a wide range pH paper. Aqueous ammonia was added
drop by drop to approximately 2 mL of beryllium sulphate, followed by a few drops of
weak hydrochloric acid. I accepted the observation. Drop by drop, 4M of sodium
hydroxide was added to approximately 2ml of beryllium sulphate and aluminum
chloride, then the solution test tubes were diluted with water and heated. Drop by
drop, 1M ammonium carbonate was added to approximately 2 ml of beryllium
sulphate and aluminium chloride solutions, which were then diluted with water and
heated. 4M sodium hydroxide was added drop by drop to approximately 2ml of
beryllium sulphate, magnesium chloride, and calcium chloride solutions in test tubes.
Extra sodium hydroxide was added to each test tube and stirred. A solution of
beryllium sulfate (0.3g) in water (3ml) was treated with 4M aqueous ammonia until
precipitation was complete. glacial acetic acid was added to beryllium hydroxide.
Evaporated the solution in a water bath, then added a few drops of water and
evaporated it until it was dry. The dry product's solubility in water, ethanol, diethyl
ether, and light petroleum was investigated.
RESULTS
EXPERIMENT OBSERVATION EXPLANATION
1. The universal indicator When beryllium combines with
a) Test the pH of a didn’t change colour, it sulphuric acid, the results are
solution of beryllium remained red (pink). beryllium sulphate and
sulfate hydrogen gas. Because
sulphuric acid is a powerful
acid, it affects the pH of the
solution, making it acidic.
Be+ H 2 S O 4 → BeS O 4 + H 2 . The
pH is 3, indicating that it is
acidic.
b) Test the pH of a The universal indication When magnesium combines
solution of magnesium remained red (pink) and with hydrochloric acid (a
chloride. did not change color. powerful acid), magnesium
chloride and hydrogen gas are
formed. Because hydrochloric
acid affects the pH of the
solution, it becomes acidic.
c) Test the pH of a The litmus paper's color Because aluminium interacts
solution of aluminium stayed red (pink). There with HCl to generate
chloride had been no change. aluminium chloride, the
solution is acidic. HCl is a
powerful acid.
2. BeSO4 solution + When aqueous The cloudiness is caused by a
aqueous NH3 ammonia was single displacement process,
dropwise until excess. introduced dropwise, which results in precipitates in
cloudiness occurred, the solution and the creation of
and two immiscible hydrogen gas.
 layers of bubbles and
cloudiness were
present. The solution
was clear in excess,
with the top layer of
bubbles still visible.
Add dil. HCl to solution in The solution became This is because BeSO4
2.
transparent when dilute solution contains an alkaline
hydrochloric acid was metal, which is less reactive,
added, and when too and hence no chemical
much was added, a reaction occurred.
layer of bubbles
developed on top.
3. There was some The cloudiness is caused by
a) BeSO4 solution + 4M milkiness in the solution the precipitation of precipitates
NaOH dropwise until when 4M NaOH was in the solution and the creation
excess. added dropwise, but of hydrogen gas.
when it was added in
excess, the solution
turned clear.
Dilute the solution in 3(a) There was no Because BeSO4 solution
and boil discernible change contains an alkaline metal,
when it was cooked. which is less reactive, no
The solution remained chemical reaction occurred.
clear.
b) AlCl3 solution + 4M The solution got hazy as The cloudiness was caused by
NaOH dropwise until sodium hydroxide was precipitates that formed in the
excess. added dropwise, but solution; as more NaOH was
cleared after the sodium added, the precipitates were
hydroxide was added in dissolved.
excess.
Dilute the solution in 3(b) There was no The little bubbles are caused
and boil discernible change by the solution creating
when the solution was
 diluted with water; it hydrogen gas.
stayed clear, and it
remained clear even
after boiling.
4. When ammonium An alkaline metal in BeSO4
a) BeSO4 solution + carbonate was added solution reacted to generate an
(NH4)2CO3 solution dropwise, cloudiness insoluble carbonate.
dropwise until excess arose, and in excess,
the solution became
completely cloudy.
Dilute the solution in 4(a) When diluted with water, Carbonate is the insoluble
and boil the solution became precipitate.
cloudy, and the
precipitate remained at
the top after boiling.
b) AlCl3 solution + The solution became The cloudiness is caused by
(NH4)2CO3 solution drop milky, and in excess, it precipitates that form in the
wise until excess became cloudy with solution and the production of
greater foam on top. hydrogen gas.
Dilute the solution in 4(b) After being diluted with Water did not immediately
and boil water, the solution react with the solution,
remained cloudy and resulting in the formation of
after heating, a two layers, demonstrating that
precipitate formed. the reaction between water
and the b) AlC l 3 solution+¿
solution is not spontaneous.
5. When the sodium The cloudiness is caused by
a) BeSO4 solution + 4M hydroxide was added precipitates forming in the
sodium hydroxide dropwise, the solution solution.
dropwise turned milky and
eventually cleared.
b) MgCl2 + 4M sodium When the sodium The cloudiness is caused by
hydroxide dropwise hydroxide was added precipitates forming in the
 dropwise, the solution solution.
got cloudy and then
cleared.
c) CaCl2 + 4M sodium The solution got cloudy The cloudiness is caused by
hydroxide dropwise as the sodium hydroxide precipitates forming in the
was added dropwise. solution.
6. Milky white precipitate Be ¿
a) Test the solubility of was formed Hydration and dissociation of
the product in: beryllium acetate leads to the
(i) water formation of beryllium
hydroxide and acetic acid.
Precipitate is result of reaction
between hydroxide ions and
beryllium cations.
(ii) ethanol The solution becomes Because this chemical is
cloudy with a precipitate insoluble in ethanol, a solid
precipitate form. The presence
of particles or a hazy
appearance in the solution
indicates that a chemical
change has occurred.
(iii) diethyl ether When the product is When the two substances
dissolved, it loses it contact, the oxygen atoms of
white colour and the the diethyl ether molecules
solution remain clear. create a coordination complex
with the beryllium ions. This
complexation is expected to
result in the development of a
stable chemical, which can be
seen as beryllium acetate
dissolves smoothly in diethyl
ether.
(iv) light petroleum The solution becomes Beryllium acetate, when
cloudy with precipitate. dissolved in light petroleum,
 may not be stable over time
due to hydrolysis in moisture,
causing precipitation or cloudy
solution formation.

6. b)

Figure 1: Structure of product, beryllium acetate

CONCLUSION
Group II hydroxide solubility increases from beryllium hydroxide to calcium
hydroxide, and then down to strontium hydroxide. This could be an experimental
error, as the size differences between cations and anions decrease with group size.
Alkaline earth metals Ca, Mg, and Be, have the least to greatest reactivity. Calcium
is the most reactive element, producing precipitates in solutions. Magnesium is the
second most reactive metal, with Be having a weak interaction with anion solutions
like carbonate ions. Beryllium is the least reactive element, but Ca is more reactive
than magnesium. The periodic law states that as group size decreases, the nuclei's
ability to attract electrons decreases, resulting in lower energy for outermost valence
electrons due to shielding.
References
Rayner, C. G. & Zheng, Z., 2008. Naming elements after scientists: an account of a controversy.
Foundations of Chemistry, 10(1), pp. 13-18.

Smith, J., 2015. Electron configuration and periodic trends of Group IIA elements. Journal of
Chemical Sciences, 45(2), pp. 156-162.